Mold and air quality testing in Québec City

Québec City gets about 4,754 heating degree-days a year and has a winter design temperature of −24.8°C, according to NRCan's HOT2000 climate data for Ste-Foy. On cold days, exterior corners, closets on outside walls and window frames get cold enough for condensation, which is where mold usually starts in Québec City houses.

Of Québec City's 121,435 houses (single-detached, semi-detached, row houses and duplexes), 20% were built before 1961 and 70% before 1991, according to the 2021 Census. Older basements without a moisture barrier and houses that were air-sealed without adding ventilation are common trouble spots.

• You smell mustiness but can't find the source.
• After a leak or flood, to check that cleanup worked.
• Before buying an older house with signs of past water damage.

If you can see mould, you usually don't need a test to know it's there; you need to fix the moisture and clean it up properly.

Quebec has a voluntary standard for handling mould in homes (BNQ 3009-600, 2020); no province has a mandatory residential mould standard.

Ask any Québec City tester which lab analyzes their samples, and look for one accredited under AIHA's EMLAP program for environmental microbiology. Pair sampling with a ventilation and humidity assessment, which finds the cause.

Ventilation and humidity assessments in Québec City · Our mold and indoor air quality guide